Acoustic AG60 Guitar Amp

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CJ

Well-known member
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Joined
Jun 3, 2004
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on the chopping block today is a modern Acoustic amp that has an annoying habit of tilting back, and some interesting traits like a 1/4 inch input jack that also takes a mic cable, (XLR)

this guy goes for about 400 bucks at the discount shops,


 

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darn thing hums, and does not amplify,

funny, PRR told me to use a LM3886 chip to fix an old Sears git amp,

guess what this thing uses?

that's right, a 3886, and it has a pair of DSP processors on daughrer boards so you can have two different sounds from the two channels,

 

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power components are usually the first to go, so a hunch says replace the chip,

and this did fix the amp,

sounds cool, however does not clip well, as the DSP chips do not like over driven signals, so there is a peak LED to warn you that your sound sucks,  :D

gain is real hot for guitars, you barely turn up the vol knob and the LED blinks,

so this is probably meant for acoustic guitar and mic, so you can play6 the coffee shops whit one piece of gear,

the processors sound good and the amp tilts back like a monitor, could use some ballast to keep it sitting up straight,

3886 sitting behind the wire bundle on a hefty heatsink,
 

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The dual power-amps in your last two carcasses emulate the old-old Roland JC-120.

I'm still trying to sort the JC's cross-mix network, but it appears that clean sound goes to both amps/speakers while chorus and reverb only go to one.
 
Thanks. There is another one, with separate clean and dirty preamps, where clean preamp is all JFETs not chips, unipolar supply, Line Out tapped from speaker points. Clearly the same thinking, but someone got tired of FET inconsistency.

This one is less tangled. I see that Reverb goes to both speakers. I still think that Chorus only comes out of one speaker (and that Chorus Sw transistor must have a typo).
 

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